Function emit 

pub fn emit<T: RenderOutput>(
    cli: &Cli,
    cfg: Option<&RepoConfig>,
    out: &T,
) -> Result<()>

Resolve the format decision (JSON vs text) and emit accordingly.

Centralises the should_output_json → branch → write idiom from the existing structure-first verbs. Handlers should construct a typed output value and call this; never println! directly.